1. Field of the Invention
The present invention relates to a signal processor for a video camera and, more particularly, to a color signal processor for a video camera using a CCD image sensor.
2. Description of the Prior Arts
In ordinary home video cameras, it is general to employ a CCD image sensor due to an advantage that a compact structure is achievable. An exemplary signal processor for such a video camera is disclosed in "A Single Chip CCD color Camera System Using Field Integration Mode", The Journal of the Institute of Television Engineers of Japan, Vol. 3 No. 10 (1983), pp. 855-862.
The above known technique is such that, for the purpose of equalizing luminance signals in individual fields and lines despite mixing of the signal charges of two vertically adjacent pixels, and also for obtaining at least two kinds of color signals in two horizontal lines, two-pixel mixed reading color filters including yellow (ye), cyan (Cy), magenta (Mg) and green (G) filters are used which are arrayed to form plural matrices of two columns and four rows. Accordingly, there is obtained in each horizontal line a luminance signal (2R+3G+2B) based on (Ye+Mg)+ (Cy+G) or (Ye+G)+(Cy+Mg). There are also obtained, in every other line sequentially, a near blue color difference signal 2R-G based on (Ye+Mg)- (Cy+G), and a near red color difference signal 2B-G based on (Cy+Mg)-(Ye+G). In such prior art, however, white balance adjustment is performed with respect to the color difference signals, so that the composition of the color difference signals is changed in conformity with the white balance adjustment. This consequently brings about deterioration of the color reproducibility.
Furthermore, since the color difference signals are line sequential, the vertical color resolution becomes low to eventually raise a problem that false color signals are prone to be formed.